Methods and Apparatuses for Determination of Hot Flashes

Abstract

The subject invention provides methods and apparatuses that determine or characterize a physiological condition known as a “hot flash” in a subject. Embodiments include interdigitated sensors and control systems that determine measures of a plurality of impedance, capacitance, AC resistance, phase, DC resistance, and temperature of the skin of a subject using a plurality of electrodes at a plurality of measurement times over a total measurement period. Embodiments determine a composite capacitance, a combined phase, or a combination thereof, and determine or characterize a hot flash therefrom.

What is claimed is: 
     
         1 . An apparatus for the determination of a physiological condition known as a hot flash, comprising:
 (a) an interdigitated sensor;   (b) a control system configured to apply electrical signals to the interdigitated sensor and collect signals from the interdigitated sensor;   (c) an analysis system configured to accept signals from the interdigitated sensor, and to determine the presence, intensity, duration, or a combination thereof, of a hot flash from the interdigitated sensor signals.   
     
     
         2 . The apparatus of  claim 1 , further comprising a skin temperature sensor, and wherein the control system is further configured to collect signals from the skin temperature sensor, and wherein the analysis system is further configured to determine the presence, intensity, duration, or a combination thereof, of a hot flash from the interdigitated sensor signals and the skin temperature signals. 
     
     
         3 . The apparatus of  claim 1 , further comprising an ambient temperature sensor, and wherein the control system is further configured to collect signals from the ambient temperature sensor, and wherein the analysis system is further configured to determine the presence, intensity, duration, or a combination thereof, of a hot flash from the interdigitated sensor signals and the ambient temperature signals. 
     
     
         4 . The apparatus of  claim 1 , wherein the interdigitated sensor comprises a plurality of electrical conductors spaced apart by predetermined distances. 
     
     
         5 . The apparatus of  claim 4 , wherein the electrical conductors are coated with a dielectric that prevents direct electrical contact between the electrical conductors and the skin of a subject. 
     
     
         6 . The apparatus of  claim 4 , wherein the interdigitated sensor comprises three electrical contacts, each having a plurality of fingers disposed on ⅔ of the circumference of each of a plurality of concentric circles, where each electrical contact is centered the circumference of one of the circles and the centers of the electrical contacts are equally spaced about such circumference, and wherein the fingers of each electrical contact are interdigitated with the fingers of adjacent electrical contacts. 
     
     
         7 . The apparatus of  claim 4 , wherein the interdigitated sensor comprises first, second, and third electrical contacts, each comprising a plurality of fingers, wherein fingers of the first electrical contact are interdigitated with fingers of the second electrical contact and separated by a first distance, and fingers of the second contact are interdigitated with fingers of the third contact and separated by a second distance, where the second distance is different than the first distance. 
     
     
         8 . The apparatus of  claim 1 , wherein the interdigitated sensor comprises first and second electrical contacts, each contact having fingers disposed in a fractal pattern. 
     
     
         9 . The apparatus of  claim 1 , wherein the control system is configured to apply an electrical signal to the interdigitated sensor, wherein the electrical signal comprises an alternating voltage at a frequency from 5 kHz to 95 kHz. 
     
     
         10 . The apparatus of  claim 1 , wherein the analysis system is configured to determine the presence of a hot flash when the signals collected from the interdigitated sensor indicate a capacitance from 0.1 nF to 0.4 nF. 
     
     
         11 . The apparatus of  claim 1 , wherein the analysis system is configured to determine the presence of a hot flash when the signals collected from the interdigitated sensor indicate a decrease in capacitance from of 0.01 to 0.08 nF within 10 seconds. 
     
     
         12 . The apparatus of  claim 11 , wherein the analysis system is configured to determine the presence of a hot flash when the signals collected from the interdigitated sensor indicate a decrease in capacitance from of 0.03 to 0.05 nF within 5 seconds. 
     
     
         13 . A method of determining the presence, intensity, duration, or a combination thereof, of a hot flash, comprising:
 (a) determining a measure of a plurality of impedance, capacitance, AC resistance, phase, DC resistance, and temperature of the skin of a subject using a plurality of electrodes at a plurality of measurement times over a total measurement period;   (b) determining the presence, intensity, duration, or a combination thereof, of a hot flash from the measures determined in step (a).   
     
     
         14 . The method of  claim 13 , wherein step (a) comprises providing an apparatus as in  claim 1 , and using the apparatus to determine a measure of a plurality of impedance, capacitance, AC resistance, phase, DC resistance, and temperature of the skin of a subject using a plurality of electrodes at a plurality of measurement times over a total measurement period. 
     
     
         15 . The method of  claim 13 , wherein step (a) comprises determining a composite capacitance, a combined phase, or a combination thereof. 
     
     
         16 . The method of  claim 13 , wherein step (a) comprises applying an electrical signal to an interdigitated sensor, wherein the electrical signal comprises an alternating voltage at a frequency from 5 kHz to 95 KHz. 
     
     
         17 . The method of  claim 13 , wherein step (b) comprises determining the presence of a hot flash when the signals collected from the interdigitated sensor indicate a capacitance from 0.1 nF to 0.4 nF. 
     
     
         18 . The method of  claim 13 , wherein step (b) comprises determining the presence of a hot flash when the signals collected from the interdigitated sensor indicate a decrease in capacitance from of 0.01 to 0.08 nF within 10 seconds. 
     
     
         19 . The method of  claim 13 , wherein step (b) comprises determining the presence of a hot flash when the signals collected from the interdigitated sensor indicate a decrease in capacitance from of 0.03 to 0.05 nF within 5 seconds. 
     
     
         20 . The method of  claim 13 , wherein step (a) comprises determining a composite capacitance and a skin temperature, and wherein step (b) comprises determining a start of a hot flash when the composite capacitance increases at the same time as the skin temperature decreases.